25 July 1997

Fusarium now can spell future threat

HEAVY fusarium infections this summer pose a severe threat to next years crops.

Fusarium ear blight is widespread after ideal infection conditions during flowering, explains John Clement, researcher at Harper Adams Agricultural College.

"A lot of inoculum will be carried over on contaminated grain and in crop debris and we could get very high levels of foot rot next spring. That could lead to quite serious yield losses."

Soil-borne fusarium is known to produce mycotoxins in grain samples. But latest HGCA-funded work in conjunction with ADAS and CSL shows yield also suffers. "Three years of field trials at Harper by Dr Peter Jenkinson show that for every 10% increase in ear blight in a potential 8t/ha wheat crop you can lose 0.5t/ha.

Biggest risk from fusarium is to autumn establishment, especially in sowings after October, says ADAS pathologist Bill Clark. "Fusarium on seed is very serious."

Where the disease is obvious in intended seed crops treatment is a must, he advises. "But you can still have high levels even if you cant see it, so testing is essential."

All commercial seed treatments offer good fusarium control, says Mr Clark. "You would struggle to separate them on activity. To say one is better than another is splitting hairs."

Much is made of mycotoxins, he adds. "But there is no relationship between levels of fusarium in the field and mycotoxins in store." Storage conditions are the key to whether problems arise, he explains.

&#8226 Low grain prices and the high risk of fusarium in this years crops mean growers should seriously think about using grain from last years harvest as seed, says Cambs-based consultant Paul Spackman. "If you have any grain left on farm, consider having it tested for seed use, even untreated it could be healthier that what you may buy in this autumn," he suggests.

Fusarium (inset) poses a big risk to seed sowings this autumn, say pathologists.

FUSARIUM

&#8226 Heavy infection this summer.

&#8226 High carry over inoculum.

&#8226 Autumn establishment risk.

&#8226 Yield and quality penalties.

&#8226 Seed treatment advised.